Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for receiving system information in a wireless communication system.
Related Art
Universal mobile telecommunications system (UMTS) is a 3rd generation (3G) asynchronous mobile communication system operating in wideband code division multiple access (WCDMA) based on European systems, global system for mobile communications (GSM) and general packet radio services (GPRS). A long-term evolution (LTE) of UMTS is under discussion by the 3rd generation partnership project (3GPP) that standardized UMTS.
Inter-cell interference coordination (ICIC) has the task to manage radio resources such that inter-cell interference is kept under control. ICIC mechanism includes a frequency domain component and time domain component. ICIC is inherently a multi-cell radio resource management (RRM) function that needs to take into account information (e.g. the resource usage status and traffic load situation) from multiple cells. The preferred ICIC method may be different in the uplink and downlink.
The frequency domain ICIC manages radio resource, notably the radio resource blocks, such that multiple cells coordinate use of frequency domain resources.
For the time domain ICIC, subframe utilization across different cells are coordinated in time through backhaul signaling or operation, administration, and maintenance (OAM) configuration of so called almost blank subframe (ABS) patterns. The ABSs in an aggressor cell are used to protect resources in subframes in the victim cell receiving strong inter-cell interference. ABSs are subframes with reduced transmit power (including no transmission) on some physical channels and/or reduced activity. The eNB ensures backwards compatibility towards UEs by transmitting necessary control channels and physical signals as well as system information. Patterns based on ABSs are signaled to the UE to restrict the UE measurement to specific subframes, called measurement resource restrictions. There are different patterns depending on the type of measured cell (serving or neighbor cell) and measurement type (e.g. RRM, radio link monitoring (RLM)). Multicast-broadcast single frequency network (MBSFN) subframes can be used for time domain ICIC when they are also included in ABS patterns. The eNB cannot configure MBSFN subframes as ABSs when these MBSFN subframes are used for other usages (e.g., multimedia broadcast multicast service (MBMS), location service (LCS)).
ICIC is located in the eNB.
When ICIC is configured, a method for receiving system information efficiently may be required.